1. Field of the Invention
The present invention generally relates to golf balls and more particularly to golf balls having components made of polyalkenamer/ionomer/polyamide blended compositions. The golf ball includes a core having at least one layer and cover having at least one layer. The golf ball may include at least one intermediate layer disposed between the core and cover. The resulting ball has high resiliency, durability, good scuff-resistance, and a soft feel.
2. Brief Review of the Related Art
Multi-piece solid golf balls having an inner core and outer cover with at least one intermediate layer disposed there between are popular today among professional and recreational golfers. In such balls, the inner core is made commonly of a natural or synthetic rubber, such as polybutadiene, styrene butadiene, poly(cis-isoprene), or poly(trans-isoprene), or highly neutralized acid copolymers. Often, the intermediate layer is made of an olefin-based ionomer resin that imparts hardness to the ball. These ionomer acid copolymers contain inter-chain ionic bonding, and are generally made of an α-olefin such as ethylene and a vinyl comonomer having an acid group such as methacrylic, acrylic acid, or maleic acid. Metal ions such as sodium, lithium, zinc, and magnesium are used to neutralize the acid groups in the copolymer. Commercially available olefin-based ionomer resins are available in various grades and identified based on the type of base resin, molecular weight, and type of metal ion, amount of acid, degree of neutralization, additives, and other properties. The outer covers of conventional golf balls are made from a variety of materials including ionomers, polyamides, polyesters, and thermoplastic and thermoset polyurethane and polyureas.
Manufacturers of golf balls are constantly looking at new materials for developing multi-piece, solid balls. Different materials can be used to impart specific properties and features to the ball. For example, Chou et al., US Patent Application publication 2009/0298372 discloses a blend comprising an ionomer and a polyamide that can be used in making multi-layered structures including floor coverings, furniture film coverings, ski tops, auto interior layers, and sporting goods such as golf balls. The ionomer is derived from at least three repeat units derived from ethylene, an α,β-unsaturated C3-C8 carboxylic acid, and a dicarboxylic acid or its derivative. The polyamides are derived from one or more lactams or amino acids and include nylon 6, nylon 11, or nylon 12.
Kim et al., U.S. Pat. No. 7,528,196 and U.S. Patent Application Publication US 2009/0191981 disclose a golf ball comprising a core, cover layer, and optionally one or more inner cover layers, wherein at least one portion of the ball comprises a blend of a polyalkenamer and polyamide. The polyalkenamer/polyamide composition contains about 2 to about 90 weight % of a polyalkenamer polymer and about 10 to about 98 weight % of a polyamide. The '196 patent and '981 Published Application further disclose that the polyalkenamer/polyamide composition may be blended with other polymers including unimodal ionomers, bimodal ionomers, modified unimodal ionomers, and modified bimodal ionomers. However, neither the '196 patent nor '981 Published Application discloses a composition comprising i) about 10 to about 65 weight percent of a polyalkenamer rubber; ii) about 30 to about 80 weight percent of an ionomeric resin; and 3) about 5 to about 40 weight percent of a polyamide.
One objective of the present invention is to develop compositions that can be used to make a golf ball having high resiliency, durability, and scuff-resistance along with a comfortable and soft “feel.” The present invention provides golf ball core compositions having such properties as well as other advantageous characteristics, features, and benefits.